Gear assembly and surgical instrument with a gear assembly

ABSTRACT

A gear arrangement including two drive units ( 210, 220, 310, 320, 410 ), and two translatory transmission elements ( 151, 152, 251, 252, 351, 352 ), to each of which a rotationally movable function unit ( 141, 142 ) of a distally arranged two-part end effector ( 140 ) can be coupled. The first drive unit ( 210, 310, 410 ) has at least one proximally arranged rotation element ( 311, 411 ) or a thrust element ( 210 ) for opening or closing the end effector ( 140 ) by rotation of at least one function unit ( 141, 142 ). The second drive unit ( 220, 320 ), with which the translatory transmission elements ( 151, 152, 251, 252, 351, 352 ) are movable in opposite directions, has at least one proximally arranged rotation element ( 224, 320, 421 ) for simultaneous and unidirectional pivoting of the function units ( 141, 142 ) of the end effector ( 140 ). A surgical instrument includes the gear arrangement ( 200, 300, 400 ) in the handle ( 180 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119 ofGerman Application DE 10 2017 114 838.8, filed Jul. 4, 2017, the entirecontents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention pertains to a gear arrangement and a surgicalinstrument with a gear arrangement.

BACKGROUND OF THE INVENTION

In minimally invasive surgery (MIS), a surgical instrument is insertedinto a body through a natural opening, or through an opening created bythe surgeon, in order to withdraw samples or perform interventions atpredetermined locations. Hand-held instruments available for minimallyinvasive surgery are generally rigid. When using such rigid instruments,only a limited number of degrees of freedom are available to thesurgeon.

If an end effector on the instrument head, for example in the form offorceps, scissors or grippers, is inserted into the interior of a humanbody, the head of a manually controlled instrument can often only beopened or closed and rotated about the longitudinal axis of the shaft,which is in most cases rod-shaped. The freedom of movement of thesehand-held devices is restricted and thus also limits the maneuverabilityof the surgeon. A limited maneuverability may unnecessarily prolong theoperation and may possibly increase the risk of the patient sufferingcomplications.

Most of the manually guided minimally invasive instruments have too fewdegrees of freedom, or the instrument head and transmission mechanism isnot sufficiently stable, for example in order to be able to suture ordissect with precision. In order to permit further degrees of freedom,such as pivoting of the end effector, complicated mechanicalconstructions are needed. The necessary mechanical gear ratio does notpermit intuitive and precise control. Lack of stability and forcetransmission are known problems of these systems. Moreover, depending onthe experience of the person operating, manual control of severaldegrees of freedom with mechanical instruments requires lengthy periodsof training and a great deal of dexterity, such that a robot-assistedapproach or the integration of electrical actuators is often preferredover manually guided instruments, in order to obtain pivoting of thefunctional end of the instrument.

SUMMARY OF THE INVENTION

An object of the invention is to make available an improved manuallyguided instrument for minimally invasive surgery. It is in particular anobject to make available a surgical instrument with improved operatorcomfort and instrument maneuverability.

A further object of the invention is to provide the operator with aminimally invasive instrument having sufficient freedom of actuation,and having an extended working range of the instrument head, withoutusing robotic systems,

A further object of the invention is to mechanically decouple thedegrees of freedom of a manually guided instrument from each other inorder to provide the operator with a control element for each degree offreedom and to provide a more stable instrument geometry.

The invention is intended to overcome the abovementioned disadvantages,in particular the restricted freedom of movement of conventionalmechanical instruments. The transmission of force from the drive unitsto a two-part end effector is intended to be optimized. Therefore, theobject of the invention is to develop a mechanical, manually guidedmedical instrument and to make available an improved gear arrangement.

These objects are achieved by a gear arrangement according to theinvention and by a surgical instrument with a gear arrangement accordingto the features of the main claim. Preferred embodiments such as a geararrangement based on a whiffletree mechanism or a planetary geartransmission mechanism are included in the present invention.

According to a first aspect of the invention, a gear arrangement is madeavailable comprising two drive units, and two translatory transmissionelements, to each of which a rotationally movable function unit of adistally arranged two-part end effector can be coupled. The first driveunit has at least one proximally arranged rotation element or a thrustelement for opening or closing the end effector by means of rotation ofat least one function unit. The second drive unit, with which thetranslatory transmission elements are movable in opposite directions,has at least one proximally arranged rotation element for lateralpivoting of the end effector by means of unidirectional rotation of bothfunction units.

In this way, as the first degree of freedom of the end effector, theopening or closing of the end effector can be actuated by means of atleast one degree of freedom of a function unit with its own separatedrive unit. An opening or closing of the end effector can be broughtabout in which at least one function unit is moved with respect to theother function unit. In an advantageous embodiment, the drive unit isconfigured to simultaneously rotate both function units toward eachother or away from each other in order to generate, with respect to theclosed position of the end effector, an opening angle which preferablycomprises an angle range from 0° to 90° relative to the center axis orlongitudinal axis of the transmission elements.

With the aid of the second drive unit of the gear arrangement accordingto the invention, a second degree of freedom, namely the lateralpivoting or kinking of the function units of the end effector, canadvantageously be generated. By means of the at least one rotationelement of the second drive unit, both function units of the endeffector can be pivoted simultaneously and in the same direction into apivoting angle. By the combination of the two drive units, the surgicalinstrument can be actuated, i.e. opened or closed, in each of thepivoted positions with the aid of a suitable control element.

By means of the second drive unit, interventions can advantageously beperformed with a two-part end effector not only in the customary way inan axial orientation of the instrument shaft but also laterally thereof.In this way, the operator or a surgeon can choose between two degrees offreedom and can thus perform a minimally invasive intervention throughextremely small openings.

Through the additional degree of freedom of the lateral pivoting, themaneuverability of the end effector inside the body can be improved,which represents an important improvement for applications in minimallyinvasive surgery.

According to a further aspect of the invention, the translatorytransmission elements between the end effector and the drive units arearranged in an elongate shaft, at the proximal end of which is arrangeda handle with at least one control element that can be assigned to adrive unit.

The translatory transmission elements can be configured as a pull/pushrod or as a flexible element, for example a cable.

An elongated shaft is constructed specifically for minimally invasivesurgery so as to be able to be inserted through extremely small bodyopenings. A gear arrangement integrated in the handle or in the handlehousing is provided at the proximal end of the so-called long shaftinstrument. There is the possibility of rotating the entire gear aboutthe axis of the instrument shaft in order to bring about a rotation ofthe instrument.

As a suitable control element for the pivoting drive, it isadvantageously possible to provide a pivoting body that can becontrolled intuitively. To simplify the control of the end effector, therespective pivoting angle of the pivoting body can be converted into acorresponding pivoting angle of the medical instrument.

According to a further aspect of the invention, a function unit of theend effector is chosen from the group comprising: grippers, scissors,clamp, jaw part, expander, and applicator forceps jaw for clips orstaples.

The stated function units can be coupled in different shapes and sizesappropriate for the purpose, and for the corresponding use as gripping,clamping and/or cutting instruments, on the distal end of thetransmission elements. Moreover, jaw parts can be parts of forceps orpincers and can in part additionally have a toothed profile or a textilefabric covering in order to be able to protect tissue while being ableto grip it securely. Possible uses for the various function units aredissecting, cutting, gripping, lifting, retracting, holding. By means ofattachment of applicator forceps or the like, the surgical instrumentcan be used for suturing, ligaturing, clamping or clipping or forapplying staples. Said elements, which can be held by the forceps limbs,can be inserted into the body of a patient and used, for example, toclamp off vessels or the like.

According to a further aspect of the invention, the gear arrangement isbased on a whiffletree mechanism and has a whiffletree which connectsthe transmission elements in each case in the region of their proximalend, wherein the first drive unit for opening and closing the endeffector is configured as a linearly displaceable thrust element whichis arranged centrally on the whiffletree in order to produce aunidirectional linear movement of both transmission elements andtherefore a contradirectional rotary movement of both function unitsrelative to each other.

The whiffletree, which can be made available in the form of a simplerod, represents a simple and cost-effective mechanism by which therespective negative or positive thrust force of the first drive unit canbe transferred uniformly to both transmission elements.

According to a further aspect of the invention, the whiffletree, at atleast one of its ends, is connected to the rotation element of thesecond drive unit via at least one connecting rod in order to transmit,in accordance with a pivoting of the rotation element configured as arod, a drive torque to the whiffletree for the purpose of pivoting theend effector.

The whiffletree, by means of a simple right angle composed of rotationrod and connection rod, can be manually pivoted such that one limb ofthe preferably centrally angled whiffletree moves toward a transmissionelement in order to impart a positive thrust, while the other limb movesaway from the other transmission element in order to exert a negativethrust. The in this case right-angled pivoting drive unit forms apivoting body which can be controlled by hand and which is easy tocontrol.

According to a further aspect of the invention, the whiffletree has atthe center a rigid obtuse angle and, together with at least one furtherconnection rod between the free ends of the rotation element and of thewhiffletree, forms a polygonal pivotable grip piece as a control elementfor pivoting the end effector by means of contradirectional movements ofthe translatory transmission elements.

By providing connection rods on both sides of the whiffletree, aframework or polygon is formed which represents a more stable pivotingdrive unit than a simple angle. In this way, the two translatorytransmission elements coupled to the whiffletree can be actuated moreprecisely in opposite directions. The frameworks of the polygon composedof the rods of the drive unit and of the angled whiffletree preferablyform a pentagon which, in the neutral position or non-pivoted basicposition of the end effector, can approximate the circular arc movementsof the instrument head. The polygon, rotatable about a rotation axis,can be easily gripped and controlled by the operator as a grip structurethat is rotatable relative to the instrument shaft.

According to a further aspect of the invention, at least one drive unitof the gear arrangement is based on a planetary gear transmissionmechanism, wherein the rotation element of the second drive unit or ofthe pivoting drive is configured as a sun gear that can be driven inrotation, wherein a first planet gear and a second planet gear fortaking up a drive torque are in constant toothed engagement with the sungear and resulting moments of the planet gears can be conveyed to arespective planet carrier. The transmission elements are each coupled toa planet carrier in order to be movable in opposite directions duringthe driving of the sun gear.

If only the pivoting drive unit is configured as a planetary gear, it isnecessary to be able to move the transmission elements additionally inthe same direction in order to open or close the end effector. This canbe achieved by further rotation elements in the planetary gear or by athrust element which can be coupled to the end regions of thetransmission elements (as in the whiffletree mechanism). By avoiding alarge number of drive elements and motors, the surgical instrument and agear arrangement that can be integrated therein remain structurallysimple, which results in lower manufacturing costs.

According to a further aspect of the invention, the sun gear can bedriven in rotation directly or indirectly via a further coaxiallyarranged rotation element connected fixedly to the sun gear, when thesun gear or rotation element is selectively in toothed engagement withan outer toothing of a pivotable gearwheel segment of a control element.

By means of a selective toothed engagement, the operator can choosewhether the sun gear runs free or is intended to function as a driveunit by means of a movement of the gearwheel segment.

According to a further aspect of the invention, the at least onerotation element of the first drive unit is configured as a first ringgear segment that can be driven in rotation, wherein the first planetgear for taking up a drive torque is in constant toothed engagement withthe first ring gear segment and resulting moments of the first planetgear can be conveyed to the first planet carrier. By means of the firsttransmission element, the output of the first planet carrier can beconverted, according to the chosen direction of drive rotation of thering gear segment, into a positive or negative thrust for opening orclosing the end effector by means of rotation of the couplable firstfunction unit.

According to a further aspect of the invention, the first drive unit hasa rotation element configured as a second ring gear segment, wherein thesecond planet gear for taking up a drive torque is in constant toothedengagement with the second ring gear segment, and the movement of thesecond planet gear can be conveyed to the second planet carrier. Bymeans of the second transmission element, the output of the secondplanet carrier can be converted, according to the chosen direction ofdrive rotation of the ring gear segment, into a positive or negativethrust for opening or closing the end effector by means of rotation ofthe couplable second function unit.

By the use of several drive units or driving rotation elements in thegear arrangement, an exact and separate control of degrees of freedom ispossible. On the one hand, the rotation elements configured as ring gearsegments of the first drive unit can each separately control a degree offreedom of rotation of a function unit. On the other hand, a pivoting ofthe end effector can be brought about by the second drive unit (sungear).

The use of a planetary gear is particularly advantageous for theprecision of the medical instrument. This can optimize the forcetransmission by virtue of a high degree of stiffness and lowcircumferential backflash. In particular, precise movement patterns witha very high level of reproducibility can be guaranteed. This is aprecondition for precise operating in minimally invasive surgery.

Compared to the above-described drive mechanism using a whiffletree anda polygonal framework for the approximation of a circular movement, theplanetary gear has the advantage of being based on a circular movement.

According to a further aspect of the invention, provision is made that,in the non-pivoted position of the end effector, the planet gears andassociated ring gear segments can be arranged symmetrically with respectto a center axis of the parallel transmission elements and are movablein opposite directions by control elements engaging jointly on both ringgear segments, in order to generate via the respective planet carriers aunidirectional movement of the transmission elements for opening orclosing the end effector by means of rotation of both function units.

By virtue of the symmetrical structure and symmetrical drive movements,both transmission elements can be actuated simultaneously. The geararrangement according to the invention advantageously has a sufficientrotatability of the pivotable ring gear segments relative to each other.For this purpose, the ring gear segments extend about a circumferentialangle of preferably 90° to 155°.

According to a further aspect of the invention, the first drive unit andthe second drive unit can be additively coupled via the planetary geararrangement.

A further advantage of the planetary gear lies in the possibility ofsetting in motion all of the rotation elements (sun gear, planet gearsand ring gear segments), wherein one planet gear can be driven (summinggear) with the two drive units (sun gear and ring gear segments). Theplanet carriers serving as output members each summate the momentsresulting from the drive units, i.e. the torque, if only the sun gearwere driven (with fixed ring gear segments), is added to the torque ifonly the two ring gear segments were driven (with fixed, free-wheelingor supporting sun gear).

In a further advantageous embodiment of the invention, provision is madethat at least one of the control elements is provided with a securingdevice for securing the actuating element in at least one end positionand/or one or more intermediate positions.

By the coupling to one or both of the control elements by the securingdevice, the respective control element can be locked or arrested, suchthat it does not accidentally move out of place. In addition, with thesecuring device, it is possible to easily adjust certain functionalpositions of the two-part end effector of the medical instrument, forexample the gripping or opening position of a gripper. By means ofsecuring devices for the control elements or selective disengagement ofthe drive unit, it is possible for the surgical instrument to be handledsafely and in a user-friendly way.

According to a further aspect of the invention, the at least one controlelement is configured as a lever, joystick or actuation button.

A joystick, actuation button or lever can be formed, for example, at theproximal end region of the shaft as a pivoting mechanism for the medicalinstrument. Advantageously, grip recesses or grip eyelets are providedfor control and, with just one finger or a few fingers, can be used toeasily control the pivoting angle and inclination angle of the medicalinstrument.

According to a further aspect of the invention, the translatorytransmission elements are pulling or pushing elements chosen from thegroup comprising: pull or push rod, press rod, cable pull orcombinations thereof.

When cable pulls are used, particularly tight guidance of the cablepulls in the shaft is possible, wherein the outer tube can have a smalldiameter. The cable pulls can be guided by deflection rollers and/oreyelets and can be combined with rigid thrust elements. The translatorytransmission elements convert the pivoting movement of the planet gearsabut the axis of the sun gear into an axial movement and, at the distalend of the instrument, in turn convert the axial movement of thetransmission elements into the rotation of the function units.

The invention further relates to a surgical instrument which comprises adistally arranged two-part end effector and a proximally arranged handlewith a grip part that can be gripped in the hand, and with a geararrangement having two drive units. Moreover, a shaft is made availablewhich connects the handle to the end effector and has translatorytransmission elements in order to pivot or to open or close the two-partdistally arranged end effector by means of a respective control elementarranged at the handle and by means of an associated drive unit.

The gear arrangement according to the invention in the handle of thesurgical instrument are based on the one hand on a whiffletree mechanismand on the other hand on a planetary gear and permit a purely manual,articulated, strong and ergonomic minimally invasive instrument withwhich it is possible to work with precision.

The present invention will be described in detail below with referenceto the attached figures. The various features of novelty whichcharacterize the invention are pointed out with particularity in theclaims annexed to and forming a part of this disclosure. For a betterunderstanding of the invention, its operating advantages and specificobjects attained by its uses, reference is made to the accompanyingdrawings and descriptive matter in which preferred embodiments of theinvention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1a is a schematic plan view of a head piece of a surgical grippinginstrument;

FIG. 1b is a schematic plan view of a surgical cutting instrument withan end effector, which is indicated in a pivoted position by brokenlines;

FIG. 2 is a view of an embodiment of a gear arrangement with awhiffletree mechanism;

FIG. 3 is a sectional view through a further embodiment of a geararrangement with a planetary gear transmission mechanism;

FIG. 4a is a schematic plan view of a further embodiment of the geararrangement according to the invention based on a planetary gear;

FIG. 4b is a view of the gear arrangement of FIG. 4a after actuation ofthe control unit for opening or closing an end effector; and

FIG. 4c is a view of the gear arrangement of FIG. 4a after actuation ofthe control unit for pivoting an end effector.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, FIG. 1a shows a distal head piece 100 for amedical instrument, with a two-part end effector having two interactingfunction units 141, 142 that form gripping forceps. For gripping,holding or clamping, the end effector has two distally arranged functionunits 141, 142, also called jaw parts, which are mounted rotatably aboutthe rotation axis 146 and which are each connected to a respectivetranslatory transmission element 151, 152. The transmission elements151, 152 are configured as pulling or pushing rods and can actuate thefunction units 141, 142 individually, i.e. independently of each other.The pulling or pushing rods 151, 152 run through a shaft (not shown inany detail) as far as a distally arranged handle (not shown in FIG. 1).

Each movement of the pulling or pushing rods 151, 152 is transmitted viathe joints 131, 132 to the respective jaw parts 142, 141. Moreover,joints 161, 162 are arranged at the distal end of the transmissionelements 151, 152 in order to attach at least two drive units. By meansof a control element (not shown in any detail), for example with a levermechanism, manual movements on the part of a person operating theinstrument can be transmitted via a drive unit, and via transmissionelements 151, 152 connected to the latter, to the effector e.g.dissecting forceps.

FIG. 1b is a highly schematic representation of a further embodiment ofa medical instrument according to the invention, which has a two-partend effector 140, a shaft 170, a handle 180 and a control unit 190. Inthis embodiment, the end effector 140 is configured in the form ofscissors with two cutting blades or jaw parts 141, 142. The outer tube171 of the shaft 170 is connected to the housing 181. Translatorytransmission elements 151, 152 extending parallel to each other in theinterior of the shaft 170 can be coupled to two drive units arranged inthe housing. Depending on the chosen drive unit, the translatorytransmission elements 151, 152 can each generate a positive thrust orpressure or a negative thrust. The thrust can finally be converted intothe rotation of a jaw part 141, 142. The transmission elements 151, 152thus serve to actuate the end effector 140 and can be configured as rodsor cable pulls or a combination thereof. When using cable pulls, it ispossible for the outer tube 171 to have a small diameter.

Both scissor jaw parts 141, 142 are mounted rotatably about the rotationaxis 146 and are shown in FIG. 1b in a partially opened position. Acomplete closure of the scissor jaw parts can take place by a movementof the jaw parts to each other. Opening or closing is preferablygenerated by a unidirectional movement of the transmission elements 151,152 extending in parallel along the longitudinal axis 154 of the shaft170.

FIG. 1b illustrates a pivoting movement of the end effector 140 in thedrawing plane, wherein the jaw parts 141, 142 are pivoted laterally withrespect to the longitudinal axis 154 of the shaft 170. The pivoting ofboth function units or jaw parts 141, 142 of the end effector 140 takesplace simultaneously and in the same direction about the pivoting angle149 with respect to the longitudinal axis 154 of the shaft when thetransmission elements 151, 152 are moved in opposite directions, as isindicated by the arrows 156 in FIG. 1 b.

FIG. 1b illustrates in particular a pivoting movement of the endeffector about a pivoting angle 149. The scissor jaw parts 141′, 142′pivoted in the same direction clockwise (see arrow 148) about therotation axis 146 are shown in a dot-and-dash line superposed on thenon-pivoted end effector (jaw parts 141, 142 with solid line andpivoting angle=0°).

A separate control element 192 is made available for the unidirectionalpivoting of the scissor jaw parts 141′, 142′ to a position of thescissor jaw parts 141′, 142′ inclined relative to the longitudinal axis154 of the shaft 170. The control element 192 is mounted on the handle180 in such a way as to be rotatable about a rotation axis 196, which isperpendicular to the longitudinal axis 154, such that the controlelement 192 is pivotable to both sides with respect to the longitudinalaxis 154. For the pivoting of the end effector 140, the control elementis rotated from its basic position 192 to the pivoted position 192′. Theperson operating the instrument can, for example with one or morefingers, control the control element 192 arranged at the end of thehandle 180 remote from the end effector. For this purpose, one or moregrip recesses can be provided. In addition to a lever, it is alsopossible to provide a button or joystick lever as the control element.

The pivoted position of the end effector is shown only by way ofexample. The drive unit arranged in the housing 181 of the handle andused for the pivoting permits simultaneous pivoting of the jaw parts141, 142 in an angle range of preferably 0° to 90°. If the respectivepivoting angle of the pivoting body corresponds to the pivoting angle ofthe medical instrument, the control element 192 for the pivoting drivecan be controlled intuitively. It is moreover advantageous that, in eachof the pivoted positions, the jaw parts 141, 142 can be opened or closedby actuation of a further control element of the control unit 190, whichfurther control element cannot be seen in this view.

FIG. 2 shows an embodiment of a gear arrangement 200 for moving atwo-part end effector of a surgical instrument. The gear arrangement 200comprises a whiffletree mechanism which, depending on drive units 210,220 engaging on the whiffletree 260, transmits a linear movement 215 ora rotation movement 228 to the transmission unit 250.

FIG. 2 shows schematically, as transmission unit 250, the end portionsof two translatory transmission elements 251, 252 which are configuredas pulling or pushing rods and can each be coupled at the distal ends(not shown) to a function unit of a two-art end effector. A two-part endeffector 140 can be, for example, a gripper or scissors, as shown inFIG. 1a or 1 b. Moreover, other two-part end effectors such as forcepsor applicator forceps for clips, staples or the like can be connected tothe distal ends of the transmission elements 251, 252. The pulling orpushing rods 251, 252 can be guided linearly in a shaft (not shown). Thelinear guiding is illustrated by the respective double arrows 255, 256.At both proximal ends of the transmission elements 251, 252, respectivejoint connections 261, 262 are provided which operatively connect thewhiffletree 260 to the transmission unit 250.

The whiffletree 260 extends substantially transversely with respect tothe direction of movement of the transmission elements 251, 252, whichare displaceable along the longitudinal axis of the shaft. Arrangedcentrally between the transmission elements 251, 252 is a first driveunit 210, which is configured as a displaceable thrust element which isguided linearly along a linear bearing 211. The free end of the driveunit 210 can be connected via a lever mechanism to a control element(not shown in any detail), e.g. a pivotable actuating lever. The controlelement can preferably be configured as a grip part with a grip eyeletfor a finger, such that pulling and pushing forces can be appliedequally easily with just one finger.

When the control element of the first drive unit 210 is actuated, thethrust element is moved linearly (see double arrow 215) by the pressureor tension applied by the person operating the instrument. This linearmovement is transmitted via the whiffletree 260 to both transmissionelements 251, 252, such that these move in the same direction with apositive or negative thrust in the longitudinal direction of the shaft.By means of the unidirectional movement of the transmission elements251, 252, the free ends of the jaw parts of the end effector can berotated away from each other, in the case of a sliding movement in thedirection of the end effector, and can be rotated toward each other, inthe case of a sliding movement in the opposite direction. In this way,the end effector can be opened or closed depending on the thrustdirection.

In order to bring about a pivoting of the end effector, the whiffletree260 is connected to a second drive unit 220, the latter comprising arotation element 224 in the form of a rod which is mounted rotatablyabout a pivot axis 226. In order to transmit the rotation movement 228to the whiffletree 260, connection rods 221 and 222 are provided betweenthe respective protruding ends of the whiffletree 260 and the free endsof the rotation element 224. The rods 221, 222, 224 and the whiffletree260 with an obtuse angle at the center (obtuse angle indicated by thedouble arrow at joint 216) are connected in an articulated manner viathe joints 263, 265 and 225, 223, respectively, and form a polygonal,preferably pentagonal, rod system or framework.

A pivoting movement and rotation of the drive unit 220 about the pivotaxis 240 bring about a contradirectional thrust movement of thetranslatory transmission elements 251 and 252. This differentialmovement generates, as shown in FIG. 1 b, a pivoting of the instrumenthead with respect to the longitudinal axis. The rotatable drive unit 220can be configured as a control element, e.g. a grip wheel, or can bebrought into engagement with a separate control element (as is indicatedschematically in FIG. 1b ). As the control element, it is possible, forexample, to use a lever mechanism or joystick, which are mounted so asto be pivotable with respect to a handle housing or gear housing (notshown in any detail) and to the instrument shaft.

In the neutral position shown in FIG. 2, the frameworks of the polygonconsisting of rods of the drive unit 220 and of the angled whiffletree260 approximate the circular arc movements of the instrument head.However, it should be noted that, in a pivoted position of the endeffector, the opening angle of the end effector is not linear butsinusoidal, depending on the travel of the pushing or pulling rods 251,252. To avoid this dependency, the following embodiment illustrated inFIG. 3 was developed, with a gear arrangement which is based on acircular movement.

FIG. 3 shows a schematic representation of a further embodiment of agear arrangement 300, which can move at least one function unit of aninstrument head by means of a planetary gear mechanism. With the aid ofthe planetary gear, the gear arrangement 300 according to the inventioncan convert torques 328 into linear thrust movements 355, 356 of thetransmission elements 351 and 352 and, depending on the selected driveunit 310, 320, can bring about an actuation (opening or closing) orpivoting of a two-part end effector. By comparison with an embodimentbased on a whiffletree mechanism (see FIG. 2), the use of a planetarygear has the advantage that the gear is based on a circular movement andcan function as summing gear.

The planetary gear transmission mechanism of the gear arrangement 300has a central sun gear 320, which is in engagement with a first planetgear 331 and a second planet gear 332. Each planet gear 331, 332 can beengaged via an outer toothing in an inner toothing of the ring gearsegments 311 and 312. The ring gear segments 311 and 312 are ring-shapedor crescent-shaped and can also be designated as first and second ringpart or rotation elements 311, 312 of the first drive unit 310. Eachring gear segment 311, 312 can extend over a circumferential angle ofpreferably 90° to 155° and can be rotated about the rotation axis 326 ofthe sun gear 320.

In the closed and non-pivoted basic position of the end effector, theplanet gears 331, 332 and associated ring gear segments 311, 312 arearranged symmetrically with respect to an imaginary plane of symmetry,which is perpendicular to a center axis of the transmission unit 350 orthe longitudinal axis of the shaft (not shown in any detail in FIG. 3).With the aid of the symmetrical configuration of the gear, bothtranslatory transmission elements 351, 352 can be controlled. The upperhalf of the planetary gear shown in FIG. 3, in particular the planetgear 331 with the planet carrier 341 as output, can transmit linearthrust movements 355 to the upper transmission element 351, whereas thelower half of the gear arrangement can move the lower transmissionelement 352 linearly (see double arrow 356).

As the driving rotation element for the upper planet gear 331, forexample, it is possible to select either the associated ring gearsegment 311 of the first drive unit 310 or the sun gear 320 of thesecond drive unit 320. Respective control elements are provided formoving the rotation elements of the drive units 310 or 320.

As regards the first drive unit 310, control elements 391 and 393 aremade available which are each secured via a joint 360 to the outside ofa ring gear segment 311 and 312, respectively, and are configured asthrust rods. When the control element 391 is displaced according to thedouble arrow 317, the upper ring gear segment 311 moves. Thereafter, theplanet gear 331, which is at the same time supported on the sun gear320, rolls in the ring gear segment 311. As has already been explained,the movement of the planet gear 331 is taken up by the associated planetcarrier 341 and transmitted to the translatory transmission element 351.In this way, at least one function unit of the end effector can be movedwith respect to the other function unit and can thus bring about theclosing or opening of the end effector.

According to the same principle, the planet gear 332 can also be moved,wherein a movement 316 of the control element 393 is able to move thering gear segment 312. The two control elements 391, 393 canadvantageously be connected at their proximal end in order to form acontrol element 395 which, with a single movement 315, can move boththrust rods and thus in each case the rotation elements 311, 312 of thedrive unit 310. In this way, the translatory transmission elements 351and 352 can be moved simultaneously and in the same direction in orderto open and close the end effector.

The sun gear 320 serves as second drive unit 320. When the sun gear 320is rotated about the rotation axis 326 in a direction of the doublearrow 328 by means of a control element (not shown in any detail), bothplanet gears 331, 332 are rotated in the same direction.

Each planet gear 331, 332 is supported on the respective ring gearsegment 311, 312 and moves the planet carrier 341, 342 articulated onthe respective planet gear rotation axes 337, 336. In this way, aunidirectional movement of the planet carriers 341, 342 about the commonrotation axis 326 is generated, as a result of which a contradirectionalmovement of the transmission elements 351 and 352 is actuated. Thejoints 361, 362 are used to transmit a positive or negative thrustmovement 355, 356 to a translatory transmission element 351, 352,respectively. The contradirectional thrust movements generate a pivotingof an end effector (not shown here).

The way in which a gear arrangement 400 according to the inventionfunctions is shown by way of example on the basis of schematicrepresentations of the planetary gear before and after actuation of therespective drive units 410, 420 in FIGS. 4a, 4b and 4c . The geararrangement 400 shown in FIG. 4 comprises substantially the sameplanetary gear mechanism with the planet gears 331, 332 and the planetcarriers 341, 342 as output elements, as in the illustrative embodiment300 shown in FIG. 3. Therefore, the same reference signs are used todesignate identical parts. The parts that differ from the aboveillustrative embodiment 300 are identified with new reference signs.

FIG. 4, in contrast to FIG. 3, shows ring gear segments 411 and 412 witha smaller circumferential angle of approximately 90-95°. Moreover, thering gear segments 411 and 412 are each arranged on a rotary disksegment 414, 413 mounted rotatably around the sun gear axis 326. Thecontrol elements 491 and 493 are mounted on the outside, i.e. on theside directed away from the planet gear. The control element 491 isangled in such a way that it overlaps the free end of the controlelement 493 and can be connected to the latter in an articulated manner.In this way, both control elements 491, 493 can be operated as a controlunit 495 and can be displaced in the direction of the double arrow 415.

Moreover, a control element 492 in the form of a lever pivotable aboutthe rotation axis 496 is made available, which is connected to agearwheel segment 425. As is shown in FIG. 4a , the outer toothing ofthe gearwheel segment 425 can be locked at a distance from the outertoothing of the rotation element 332 such that the rotation element 322and the larger sun gear 321 connected thereto are in freewheel. Afurther position of the control element is shown in FIG. 4b , whereinthe gearwheel segment 425 engages in the teeth of the rotation element322. This position can advantageously be locked in order to function asa blocking control of the sun gear 321. When the sun gear 322 is fixedin this way, it serves as a support gear for the peripheral planet gears331, 332. This securing mechanism can be used if the first drive unit410 is actuated, as is shown in FIG. 4 b.

FIGS. 4a and 4b are schematic representations of the gear arrangement400 before and after actuation of the first drive unit 410. The firstdrive unit 410 is configured for opening and closing a distally arrangedend effector, wherein a unidirectional movement of the transmissionelements 351, 352 and hence a contradirectional movement of therotatable function units of the end effector can be brought about. Forthis purpose, the control element 495 or the two control units 491 and493 are displaced at the same time in the direction of the transmissionunit 350. The displaced control elements 491′, 493′ are shown in FIG. 4b, and also the rotated ring gear segments 411′ and 412′. The planet gear331′ is moved with the counterclockwise rotated ring gear segment 411′and thus shifts its rotation axis 336′, and the end of the planetcarrier 341 articulated thereon, in the direction of the transmissionunit 350. Similarly, the clockwise rotated planet gear 332′ takes up thedrive force transmitted by the ring gear segment 412′ and transmits thisto the coupled planet carrier 342. The coupling elements 461, 462 areconfigured as a stable sleeve extending in the longitudinal directionand can each convert the movement of the planet carriers 341, 342 intounidirectional translatory movements 355, 356 of the transmissionelements 351 and 352.

FIG. 4c shows the gear arrangement when the second control element 493and thus the second drive unit in the form of a sun gear 421 isactuated. The second drive unit or the sun gear 421 is configured forpivoting a distally arranged end effector, wherein a contradirectionalmovement 355′, 356′ of the transmission elements 351, 352 and hence aunidirectional movement of the rotatable function units of the endeffector can be brought about. To pivot an end effector, the sun gear421 is used as drive unit 320, such that in this configuration the ringgear segments 411, 412 serve only for support. For the rotation of thesun gear 421, the gearwheel segment 425′ is pivoted counterclockwise bymeans of the control element or pivoting lever 492 and thereby engagesin the teeth of the rotation element 422′. This generates a clockwiserotation movement of the rotation element 422′ and therefore of thecoaxially mounted sun gear 421′. The movement of the sun gear 421′ istransmitted to both planet gears 331′ and 332′, wherein the rotationaxis 337′ is moved away from the transmission unit, while the rotationaxis 336′ is moved toward the transmission unit 350. In this way, thetransmission elements 351, 352 are moved in opposite directions 355′,356′ and thereby generate a pivoting of the end effector.

The embodiments of the gear arrangement according to the invention andof a surgical maneuvering device, described above and shown in thefigures, can be used in all fields of medicine and in particular inendoscopy. Its use in minimally invasive surgery is particularlypreferred. However, the present invention can also be used for otherapplications, for example technical inspections of cavities.

A gear arrangement is made available which two drive units 210, 220,310, 320, 410, and two translatory transmission elements 151, 152, 251,252, 351, 352, to each of which a rotationally movable function unit141, 142 of a distally arranged two-part end effector 140 can becoupled. The first drive unit 210, 310, 410 has at least one proximallyarranged rotation element 311, 411 or a thrust element 210 for openingor closing the end effector 140 by means of rotation of at least onefunction unit 141, 142. The second drive unit 220, 320, with which thetranslatory transmission elements 151, 152, 251, 252, 351, 352 aremovable in opposite directions, has at least one proximally arrangedrotation element 224, 320, 421 for simultaneous and unidirectionalpivoting of the function units 141, 142 of the end effector 140. Thepresent invention further relates to a surgical instrument with saidgear arrangement 200, 300, 400 in the handle 180. The gear arrangement200, 300, 400 according to the invention for a surgical instrument isbased, on the one hand, on a whiffletree mechanism and, on the otherhand, on a planetary gear and can be controlled by means of two controlelements 191, 192, 391, 393, 491, 492, 493 assigned to the drive units210, 220, 310, 320, 410.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

The invention claimed is:
 1. A gear arrangement for a surgicalinstrument, the gear arrangement comprising: two drive units; twotranslatory transmission elements, wherein a distally arranged two-partend effector comprises a plurality of function units, each of thefunction units being configured to be coupled to one of the twotranslatory transmission elements, wherein a first drive unit of the twodrive units has a linearly displaceable thrust element for opening orclosing the two-part end effector by rotation of at least one of theplurality of function units, wherein a second drive unit of the twodrive units has at least one proximally arranged rotation element forsimultaneous and unidirectional pivoting of the plurality of functionunits of the two-part end effector, wherein the translatory transmissionelements are movable in opposite directions via the second drive unit;and a whiffletree connected to each of the two translatory transmissionelements in a region of a proximal end of a respective translatorytransmission element of the two translatory transmission elements,wherein the linearly displaceable thrust element for opening or closingthe two-part end effector is arranged centrally on the whiffletree inorder to produce a unidirectional linear movement of the two translatorytransmission elements and a contradirectional rotary movement of thefunction units relative to each other.
 2. A gear arrangement accordingto claim 1, wherein the translatory transmission elements between thetwo-part end effector and the two drive units are arranged in anelongated shaft, wherein a handle is arranged at a proximal end of theelongated shaft, the handle comprising at least one control elementassigned to one of the two drive units.
 3. A gear arrangement accordingto claim 2, wherein the at least one control element has a securingdevice for securing the at least one control element in at least one ofat least one end position and one or more intermediate positions.
 4. Agear arrangement according to claim 2, wherein the at least one controlelement is configured as one of a lever, a joystick and an actuationbutton.
 5. A gear arrangement according to claim 1, wherein at least oneof the function units of the two-part end effector is one or more ofgrippers, scissors, a clamp, a jaw part, an expander, applicator forcepsjaw for clips or staples and combinations of grippers, scissors, aclamp, a jaw part, an expander, and applicator forceps jaw for clips orstaples.
 6. A gear arrangement according to claim 1, wherein one end ofthe whiffletree is connected to the rotation element of the second driveunit via a connection rod in order to transmit, in accordance with apivoting of the rotation element configured as a rod, a drive torque tothe whiffletree for pivoting the two-part end effector.
 7. A geararrangement according to claim 5, wherein the whiffletree has a rigidobtuse angle at a center of the whiffletree and, together with theconnection rod and an additional connection rod between free ends of therotation element of the second drive unit and of the whiffletree, formsa polygonal pivotable grip piece as a control element for pivoting thetwo-part end effector by contradirectional movements of the twotranslatory transmission elements.
 8. A gear arrangement according toclaim 1, wherein the two translatory transmission elements are pullingor pushing elements comprising one or more of a pull or push rod, apress rod and a cable pull.
 9. A surgical instrument, comprising: adistally arranged two-part end effector; a gear arrangement comprisingtwo drive units and two translatory transmission elements, wherein thedistally arranged two-part end effector comprises a plurality offunction units, each of the function units being coupled to one of thetwo translatory transmission elements, wherein a first drive unit of thetwo drive units has a linearly displaceable thrust element for openingor closing the two-part end effector by rotation of at least one of theplurality of function units, wherein a second drive unit of the twodrive units has at least one proximally arranged rotation element forsimultaneous and unidirectional pivoting of the plurality of functionunits of the two-part end effector, the gear arrangement furthercomprising a whiffletree connected to each of the two translatorytransmission elements in a region of a proximal end of a respectivetranslatory transmission element of the two translatory transmissionelements, wherein the linearly displaceable thrust element for openingor closing the two-part end effector is arranged centrally on thewhiffletree in order to produce a unidirectional linear movement of thetwo translatory transmission elements and a contradirectional rotarymovement of the function units relative to each other; a proximallyarranged handle with the gear arrangement and a grip part configured tobe gripped in a hand; and a shaft connecting the handle to the two partend effector and the shaft comprising the two translatory transmissionelements in order to pivot or to open or close the two-part end effectorby a respective control element arranged at the handle.
 10. A surgicalinstrument according to claim 9, wherein the translatory transmissionelements are movable in opposite directions via the second drive unit.